Scale on Aloes
White Aloe Scale is a pesky and resilient species of armoured scale insect. This means that they produce a hard outer coating covering the body, which protects them from external influences such as diseases and pathogens.
If your Aloes have small grey ridges or bumps forming on the leaves it probably indicates an infestation of scale insects. They seldom kill the plants they infest, but nonetheless, are definitely not a problem that will go away on its own.
What this means for your plants
They attach to the plant and suck the juice, damaging the vitality of the succulent and causing discolouration and stippling. If left untreated, aloes will begin to lose vigour, ending up covered in what a appears to be a white, fluffy waxy deposit.
Take a picture or sealed sample to your local GCA Garden Centre and allow them to recommend a spray that will not burn the tender, succulent Aloe leaves. For scale insects on other plants, spray with a recommended organic spray dilution.
TIP: Avoid spraying the soft, new leaves of ferns and tree ferns as some sprays can damage them.